////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
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// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
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////////////////////////////////////////////////////////////////////////

#if ! defined (octave_oct_fftw_h)
#define octave_oct_fftw_h 1

#include "octave-config.h"

#include <cstddef>

#include <string>

#include "dim-vector.h"
#include "oct-cmplx.h"

namespace octave
{
  class
  OCTAVE_API
  fftw_planner
  {
  protected:

    fftw_planner (void);

  public:

    // No copying!

    fftw_planner (const fftw_planner&) = delete;

    fftw_planner& operator = (const fftw_planner&) = delete;

    ~fftw_planner (void);

    enum FftwMethod
    {
      UNKNOWN = -1,
      ESTIMATE,
      MEASURE,
      PATIENT,
      EXHAUSTIVE,
      HYBRID
    };

    static bool instance_ok (void);

    static void *
    create_plan (int dir, const int rank, const dim_vector& dims,
                 octave_idx_type howmany, octave_idx_type stride,
                 octave_idx_type dist, const Complex *in,
                 Complex *out)
    {
      return instance_ok ()
        ? s_instance->do_create_plan (dir, rank, dims, howmany, stride,
                                      dist, in, out)
        : nullptr;
    }

    static void *
    create_plan (const int rank, const dim_vector& dims,
                 octave_idx_type howmany, octave_idx_type stride,
                 octave_idx_type dist, const double *in, Complex *out)
    {
      return instance_ok ()
        ? s_instance->do_create_plan (rank, dims, howmany, stride, dist,
                                      in, out)
        : nullptr;
    }

    static FftwMethod method (void)
    {
      static FftwMethod dummy;

      return instance_ok () ? s_instance->do_method () : dummy;
    }

    static FftwMethod method (FftwMethod meth)
    {
      static FftwMethod dummy;

      return instance_ok () ? s_instance->do_method (meth) : dummy;
    }

    static void threads (int nt);

    static int threads (void)
    {
      return instance_ok () ? s_instance->m_nthreads : 0;
    }

  private:

    static fftw_planner *s_instance;

    static void cleanup_instance (void)
    { delete s_instance; s_instance = nullptr; }

    void *
    do_create_plan (int dir, const int rank, const dim_vector& dims,
                    octave_idx_type howmany, octave_idx_type stride,
                    octave_idx_type dist, const Complex *in,
                    Complex *out);

    void *
    do_create_plan (const int rank, const dim_vector& dims,
                    octave_idx_type howmany, octave_idx_type stride,
                    octave_idx_type dist, const double *in, Complex *out);

    FftwMethod do_method (void);

    FftwMethod do_method (FftwMethod meth);

    FftwMethod m_meth;

    // FIXME: perhaps this should be split into two classes?

    // Plan for fft and ifft of complex values
    void *m_plan[2];

    // dist
    octave_idx_type m_d[2];

    // stride
    octave_idx_type m_s[2];

    // rank
    int m_r[2];

    // howmany
    octave_idx_type m_h[2];

    // dims
    dim_vector m_n[2];

    bool m_simd_align[2];
    bool m_inplace[2];

    // Plan for fft of real values
    void *m_rplan;

    // dist
    octave_idx_type m_rd;

    // stride
    octave_idx_type m_rs;

    // rank
    int m_rr;

    // howmany
    octave_idx_type m_rh;

    // dims
    dim_vector m_rn;

    bool m_rsimd_align;

    // number of threads.  Always 1 unless compiled with multi-threading
    // support.
    int m_nthreads;
  };

  class
  OCTAVE_API
  float_fftw_planner
  {
  protected:

    float_fftw_planner (void);

  public:

    // No copying!

    float_fftw_planner (const float_fftw_planner&) = delete;

    float_fftw_planner&
      operator = (const float_fftw_planner&) = delete;

    ~float_fftw_planner (void);

    enum FftwMethod
    {
      UNKNOWN = -1,
      ESTIMATE,
      MEASURE,
      PATIENT,
      EXHAUSTIVE,
      HYBRID
    };

    static bool instance_ok (void);

    static void *
    create_plan (int dir, const int rank, const dim_vector& dims,
                 octave_idx_type howmany, octave_idx_type stride,
                 octave_idx_type dist, const FloatComplex *in,
                 FloatComplex *out)
    {
      return instance_ok ()
        ? s_instance->do_create_plan (dir, rank, dims, howmany, stride,
                                      dist, in, out)
        : nullptr;
    }

    static void *
    create_plan (const int rank, const dim_vector& dims,
                 octave_idx_type howmany, octave_idx_type stride,
                 octave_idx_type dist, const float *in, FloatComplex *out)
    {
      return instance_ok ()
        ? s_instance->do_create_plan (rank, dims, howmany, stride, dist,
                                      in, out)
        : nullptr;
    }

    static FftwMethod method (void)
    {
      static FftwMethod dummy;

      return instance_ok () ? s_instance->do_method () : dummy;
    }

    static FftwMethod method (FftwMethod meth)
    {
      static FftwMethod dummy;

      return instance_ok () ? s_instance->do_method (meth) : dummy;
    }

    static void threads (int nt);

    static int threads (void)
    {
      return instance_ok () ? s_instance->m_nthreads : 0;
    }

  private:

    static float_fftw_planner *s_instance;

    static void cleanup_instance (void)
    { delete s_instance; s_instance = nullptr; }

    void *
    do_create_plan (int dir, const int rank, const dim_vector& dims,
                    octave_idx_type howmany, octave_idx_type stride,
                    octave_idx_type dist, const FloatComplex *in,
                    FloatComplex *out);

    void *
    do_create_plan (const int rank, const dim_vector& dims,
                    octave_idx_type howmany, octave_idx_type stride,
                    octave_idx_type dist, const float *in, FloatComplex *out);

    FftwMethod do_method (void);

    FftwMethod do_method (FftwMethod meth);

    FftwMethod m_meth;

    // FIXME: perhaps this should be split into two classes?

    // Plan for fft and ifft of complex values
    void *m_plan[2];

    // dist
    octave_idx_type m_d[2];

    // stride
    octave_idx_type m_s[2];

    // rank
    int m_r[2];

    // howmany
    octave_idx_type m_h[2];

    // dims
    dim_vector m_n[2];

    bool m_simd_align[2];
    bool m_inplace[2];

    // Plan for fft of real values
    void *m_rplan;

    // dist
    octave_idx_type m_rd;

    // stride
    octave_idx_type m_rs;

    // rank
    int m_rr;

    // howmany
    octave_idx_type m_rh;

    // dims
    dim_vector m_rn;

    bool m_rsimd_align;

    // number of threads.  Always 1 unless compiled with multi-threading
    // support.
    int m_nthreads;
  };

  class
  OCTAVE_API
  fftw
  {
  public:

    fftw (void) = delete;

    // No copying.

    fftw (const fftw&) = delete;

    fftw& operator = (const fftw&) = delete;

    static int fft (const double *in, Complex *out, std::size_t npts,
                    std::size_t nsamples = 1, octave_idx_type stride = 1,
                    octave_idx_type dist = -1);
    static int fft (const Complex *in, Complex *out, std::size_t npts,
                    std::size_t nsamples = 1, octave_idx_type stride = 1,
                    octave_idx_type dist = -1);
    static int ifft (const Complex *in, Complex *out, std::size_t npts,
                     std::size_t nsamples = 1, octave_idx_type stride = 1,
                     octave_idx_type dist = -1);

    static int fftNd (const double*, Complex*, const int, const dim_vector&);
    static int fftNd (const Complex*, Complex*, const int,
                      const dim_vector&);
    static int ifftNd (const Complex*, Complex*, const int,
                       const dim_vector&);

    static int fft (const float *in, FloatComplex *out, std::size_t npts,
                    std::size_t nsamples = 1, octave_idx_type stride = 1,
                    octave_idx_type dist = -1);
    static int fft (const FloatComplex *in, FloatComplex *out, std::size_t npts,
                    std::size_t nsamples = 1, octave_idx_type stride = 1,
                    octave_idx_type dist = -1);
    static int ifft (const FloatComplex *in, FloatComplex *out, std::size_t npts,
                     std::size_t nsamples = 1, octave_idx_type stride = 1,
                     octave_idx_type dist = -1);

    static int fftNd (const float*, FloatComplex*, const int,
                      const dim_vector&);
    static int fftNd (const FloatComplex*, FloatComplex*, const int,
                      const dim_vector&);
    static int ifftNd (const FloatComplex*, FloatComplex*, const int,
                       const dim_vector&);
  };

  extern OCTAVE_API std::string fftw_version (void);
  extern OCTAVE_API std::string fftwf_version (void);
}

#endif
